The purpose of this project is to systematically assess the physiological responses to drug combinations used to alleviate anxiety in dental outpatients. Cardiovascular and respiratory functions are monitored noninvasively by means of an impedance cardiograph, earpiece oximeter and automatic blood pressure recorder. Results of the project indicate that the combination of diazepam-fentanyl and methohexitol causes a decrease in stroke volume which is accompanied by a reflex tachycardia. This combination results in a decrease in arterial oxygen saturation. The use of diazepam alone and diazepam plus fentanyl does not result in any detectable cardiovascular or respiratory effects. The methodology employed in this study will be used to assess other intravenous, inhalational, and oral agents which can be useful for alleviateing pain and anxiety in dental outpatients.